Agricultural Waste Annona squamosa L. Young Fruit Extract: Preparation and Antibacterial Activity of Silver Nanoparticles

In the present study, we have developed an eco-friendly method to synthesize nanoparticles using the aqueous young fruit extract of Annona squamosa. Unlike conventional syntheses, which often involve toxic reagents and energy-intensive processes, our approach is sustainable, using agricultural waste as a reducing agent. Notably, an estimated 500kg per hectare of young fruit is discarded annually in the Tay Ninh Province, Vietnam, simply because it does not meet the quality standard. By converting this waste into raw materials for nanoparticle synthesis, we address both waste management and resource utilization. For the synthesis, a 1:1 (v/v) ratio of aqueous young fruit extract was combined with 50 mL of 5 mM silver nitrate. The formation of silver nanoparticles was determined using various characterization methods, including ultraviolet–visible spectroscopy (UV-Vis), field-emission scanning electron microscopy (FE-SEM), and dynamic light scattering (DLS). The 5mm silver nanoparticles could be stored at room temperature for up to three months without significant decomposition or particle aggregation. The antibacterial efficacy of these nanoparticles was tested against two bacteria, Salmonella enteria and Escherichia coli.